Why do studies using difference scores tend to have larger effect sizes than studies using other research designs?
A)There is a long-standing procedural bias in psychology to set up studies involving dependent means in such a way as to artificially favor large effect sizes.
B)The standard deviation of difference scores is usually low.
C)Because participants provide their own baseline, variance becomes a wildcard, causing the effect size to increase.
D)Because studies with dependent means usually use a large number of participants, larger effect sizes are easily detected.

Question

Quizplus · Accepted Answer

The standard deviation of difference scores is usually lower because it accounts for individual differences by subtracting one condition's score from another for the same participants. This reduction in variability tends to inflate the effect size compared to designs that do not control for individual differences as effectively.

Why Do Studies Using Difference Scores Tend to Have Larger